Connection terminal with screw type tightener

ABSTRACT

Connection terminals with screw-type tightening means wherein the direction in which the electrical conductors to be connected up are inserted is close to a line parallel to the axis of the clamp screw. An electric terminal with an axially connected screw-type tightener according to the invention is characterized in that the clamp screw is fixed to the terminal body by means of a ring which acts as a pivot for it and in that the said screw drives a mobile jaw which is guided in the direction of a fixed jaw by a ramp formed in the terminal body.

[ Apr.'9,1974

[ CONNECTION TERMINAL WITH SCREW TYPE TIGHTENER [75] Inventor: Jean Debaigt, Maisons-Laffitte,

France [73] Assignee: CGEE Alsthom, Levallois-Perret,

France [22] Filed: Dec. 26, 1972 [21] Appl. No.: 318,135

[30] Foreign Application Priority Data Dec. 31, 1971 France 71147847 [52] US. Cl 339/95 R, 339/270 R. 339/274 [51] Int. Cl H01! 9/10 [58] Field of Search 339/95, 270, 274;

[56] References Cited UNITED STATES PATENTS 3,447,122 I 5/1969 Beck 339/270 R 3,464,055 8/1969 Lescarboura 339/270 R FOREIGN PATENTS OR APPLICATIONS 271,583 6/1927 Great Britain 339/270 R Primary Examiner-Joseph H. McGlynn Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak 5 7 ABSTRACT Connection terminals with screw-type tightening means wherein the direction in which the electrical conductors to be connected up are inserted is close to a line parallel to the axis of the clamp screw. An electric terminal with an axially connected screw-type tightener according to the invention is characterized in that the clamp screw is fixed to the terminal body by means of a ring which acts as a pivot for it and in that the said screw drives a mobile jaw 'which is guided in the direction of a fixed jaw by a ramp formed in the terminal body.

13 Claims, 2 Drawing Figures CONNECTION TERMINAL WITH SCREW TYPE TIGHTENER BACKGROUND OF THE INVENTION 1. Field of the Invention The invention concerns connection terminals having screw-type clamping means for electrical conductor wires wherein the direction in which the electric conductor wires are inserted is slightly inclined in relation to the axis of the screw.

2. Description of the Prior Art Terminals of this type generally comprise a pair of clamping jaws, the one being fixed, the other mobile, a lock screw and a body which is used for accommodating and supporting the clamping jaws and the lock screw. According to a known form of construction, the lock screw moves in a tapping formed in the terminal body or in a nut supported by that body. It keeps a fixed direction, oblique in relation to the clamping plane of the jaws and close to that in which the electric conductor wires are inserted in the terminal. It drives, in a linear movement in that fixed direction, the mobile jaw to meet the fixed jaw.

That embodiment has various disadvantages. The bringing of the jaws closer together is accompanied by a shearing movement in the direction in which the electric conductor wires are inserted in the terminal, this causing a movement of these conductor wires at the instant when the lock screw is tightened. The shearing movement increases when, with a view to reducing the bulk of the terminal, the angle between the axis of the locking screw and the direction in which the electric conductor wires are inserted in the terminal is reduced. Moreover, the reactions of the clamping forces being exerted transversally on the shank of the locking screw tend to deform it.

The aim of the invention is to overcome these disadvantages. Its aim is more particularly a terminal having an axial connecting screw, in which the bringing of the jaws closer together is effected with a shearing movement of slight amplitude and in which the lock screw supports only axial efforts. It also has for its aim a connection terminal having screw-type clamping means and slight bulk and being simple and inexpensive to manufacture.

SUMMARY OF THE INVENTION An axial connection terminal according to the invention comprises: an input face for the electric conductor wires on a fixed jaw and an access face giving access to the head of an operating screw, and a supporting face for a mobile jaw, the said screw making it move linearly along its axis, the said clamping jaws and the said screw being housed in a body.

It is more particularly characterized in that on the one hand, the end of the locking screw is slightly inclined towards the direction in which the conductor wires are inserted on the fixed jaw, the said end being fixed to a ring pivoting about an axis perpendicular to that direction, the said mobile jaw being provided with means for. guiding its movement comprising, in cooperation, a pair of lugs, with a pair of ramps having a greater inclination on the said direction, so that the sliding of the said lugs along the said ramps determines the-pivoting of the screw.

According to a particular embodiment, the ring comprises a tapping in which the shank of the locking screw moves whereas the mobile jaw is installed on the locking screw and rests against the shoulder on the head of the latter.

According to another particular mode of embodiment, the ring is trapped by the end of the shank of the locking screw for which it acts as a thrust bearing, whereas the mobile jaw is provided with a tapping in which the shank of the locking screw moves.

BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics and advantages will become apparent from the following description of an embodiment given by way of an examplehaving no limiting character. This description will be made with reference to the drawing.

FIGS. 1 and 2 are longitudinal cross-sections respectively, internal and external to the body of a terminal according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the figures, 1 designates the support stand of an electric device in which is arranged a connection terminal having screw-type clamping means according to the invention. That terminal comprises on the right hand side an input face 20, giving access to a pair of clamping jaws, the one 3 being fixed, the other 4 being mobile, a locking screw 5 and a body 2 in the form ofa U- shaped trough which is used for housing and supporting the jaws 3 and 4 and the screw 5.

The bottom 21 of the trough supports the fixed jaw 3 which is constituted by a strip of a substance which is a good conductor held against the bottom of the trough 2. It is provided in the clamping zone, with transversal serrations enabling secure fixing of the electric conductor wires 7 to be connected together; This strip extends on the outside of the terminal towards a load, not shown. Its end 11 turned towards the access in the terminal of the conductor wires 7 is folded back against the rim of the end of the bottom 21 of the trough 2. It rests against a rib 12 of the support stand 1 and maintains the trough 2 on the inside of the said support stand. The locking screw 5 is arranged between the wings 22 and 23 of the gutter 2. The end of the screw is slightly inclined towards the base of the trough so that the direction of its axis forms a very small angle with the direction in which the electric conductor wires 7 are inserted. It moves in a tapped ring 6 which rests against the opposite end of the trough 2 to that in which the conductor wires 7 are inserted, by means of diametrically opposed studs 13. The bearing surfaces of the studs 13 of the ring 6 are formed by cut-out portions 8 in the form of the ridge of the rim of the wings 22 and 23 of the trough 2. For a given inclination of the screw, the pressing of the studs 13 of the ring 6 defines a pivoting axis transversal to the wings 22 and 23 and perpendicular to the direction in which the conductor wires are inserted; its trace is embodied at 24 in FIG. 2. The

mobile jaw 4 slides between the wings 22 and 23 of the trough 2. It is driven by the locking screw 5 which extends through it. It comprises two diametrically opposite lugs 10 which slide in two parallel slots. 9 and 10 formed face to face in the wings 22 and 23 of the trough 2; these slots have a greater inclination than that of the locking screw 5 in relation to the direction in which the electric conductor wires 7 are inserted.

The various parts constituting the terminal described in FIGS. 1 and 2 are unlosable. The ring 6 is held in place against the cut out portions 8 of the trough 2 by the contour of the cavity of the terminal in the support stand 1 which has a circular contraction 16 forming, with the cut out portions 8, the walls of cavities from which the studs 13 of the ring 6 cannot escape. The mobile jaw 4 is trapped by the locking screw 5. When the locking screw 5 is loosened, the mobile jaw 4 is stopped in its travel by a stop 14. To prevent that stop 14 from being forced, the length of the thread of the locking screw 5 is such that the latter escapes from the tapping of the ring 6 when the mobile jaw 4 arrives at the end of its travel against that stop 14. The locking screw 5 comprises, on the end of its shank, a cylindrical smooth portion 15 having a smaller diameter than its thread. That smooth portion 15 remains engaged in the ring 6 when the locking screw 5 is completely loosened. It enables the thread of the locking screw 5 to be automatically engaged in the tapping of the ring 6 at the beginning'of each clamping operation.

FIG. 1 shows the locking screw 5 in the loosened position; the mobile jaw is stopped by the stop 14, the end of the locking screw shank is kept engaged in the ring 6 by its smooth portion 15. FIG. 2 shows the locking screw in the average clamping position. The pitch of the locking screw 5 is engaged in the tappingof the ring 6, the mobile jaw 4 is just about in the middle of its travel; it is guided in the direction of the fixed jaw 3 by the studs and the slots 9 and 19. The operation of that terminal is simple. When the locking screw 5 is clamped; the latter rests, through the ring 6, on the opposite end of the trough 2 to that in which the conductor wires 7 are inserted and draws the mobile jaw 4 to the inside of the trough 2. That jaw, by the reaction of the guide lugs 10 in the slots 9, comes closer to the fixed jaw 3. Conversely, when the locking screw 5 is loosened, the latter rests, through the ring 6 on the contraction 16 of the support stand 1 and pushes back the mobile jaw 4. The latter, by reaction of the guide lugs 10 in the slots 9 and 19 moves away from the fixed jaw '3.

The locking screw 5 is free to pivot in a plane parallel to the clamping forces which are exerted between the jaws 3 and 4. It is subjected to no transversal stress and is not in danger of being deformed.

The clamping jaws 3 and 4 move away automatically from each other when the locking screw 5 is loosened and does not require any return spring.

The shearing movement of the mobile jaw 4 in relation to the fixed jaw 3 is that which is obtained with a terminal of known type using a locking screw having a fixed direction having the sameinclination in relation to the direction in which the conductorwires are inserted in the terminal as the guide slots 3. But that terminal would have a much greater bulk, for the direction of its locking screw would form,'with that same inserting direction, an angle which is much more open.

The manufacturing of the terminal described is simple. A molded substance may be used for the support stand 1. The body 2 of the terminal in the form of a trough may be produced from a steel sheet by folding and cutting out. The ring 6 may be produced from a nut whose outer'contour only needs to be fashioned. To

trap the mobile jaw 4 with the locking screw, it is necessary only to fit it into the shank of the screw, for example, before the latter is threaded, and to cut a screw thread by rolling, this increasing the diameter of the screw shank in its threaded portion.

Without going beyond the scope of the invention, certain arrangements may be modified and certain means may be replaced by equivalent means. More particularly, it is possible to use a non-tapped ring 6 trapped by the end of the shank of the locking screw 5 for which it will then act as a thrust bearing, the mobile jaw 4 being driven by means of a tapping in which the locking screw 5 moves. Other embodiments may also be used for pivoting the ring 6 and guiding the mobile machine 4.

The connection terminals according to the invention are of particular interest for producing the electrical connection of devices whose support stand is accessible only on one side; clamping is progressive.

I claim:

1. In an electric axial connection terminal comprising; fixed and mobile jaws; an input face for electric conductor wires on said fixed jaw and an access face for access to the head of an operating screw and for supporting said mobile jaw, said screw moving it linearly along its axis, said clamping jaws and said screw being housed in a body, the improvementwherein: the end of the screw is slightly inclined towards the direction in' which the conductor wires are inserted in the fixed jaw, said end being connected to a ring pivoting about an axis perpendicular to that direction, said mobile jawbeing provided with means for guiding its movement comprising in cooperation; a pair of lugs with a pair of ramps having a greater inclination in the said direction, so that the sliding of said lugs along said ramps determines the extent of pivoting of said screw.

2. The electric terminal according to claim 1;

wherein: the ring comprises a tapping in which the locking screw moves, and the mobile jaw is fitted onto the locking screw and rests against the shoulder of its head.

3. The electric terminal according to claim 1, wherein: the ring constitutes a thrustbearing for the end of the shank of the locking screw which keeps it trapped, and the mobile jaw is provided with a bore within whichthe locking screw rotates.

4. The electric terminal according to claim 1 wherein: the body of the terminal is constituted by a U- shaped trough at whose bottom the clamping of the conductor wires is effected.

5. The electric terminal according to claim 2 wherein; the body of the terminal is constituted by a U- shaped trough at whose bottom the clamping of the conductor wires is effected.

6. The electric terminal according tov claim 3 wherein: the body of the terminal is constituted by a U- shaped trough at whose bottom the clamping of the conductor wires is effected.

7. The electric terminal according to claim 4; wherein: said trough comprisestwo cut out portions forming ridges facing said ring, each on the rim of the trough at the opposite end to that in which the conductor wires are inserted, and the ring comprises two diameterically opposite studs which rest against said cut out portions, which determine therein, for each inclination of the screw, a pivot axis.

8. The electric terminal according to claim 4 wherein: the ramps comprise two parallel slots arranged face to face in the wings of the trough and leading to the input face of the terminal, and the mobile jaw comprises two diametrically opposite lugs which slide in the slots, providing a means for guiding it towards the fixed jaw.

9. The electric terminal according to claim 7 wherein: the ramps comprise two parallel slots arranged face to face in the wings of the trough and leading to the input face of the terminal, and the mobile jaw comprises two diametrically opposite lugs which slide in the slots, providing a means for guiding it towards the fixed jaw.

10. The electric terminal according to claim 1 I wherein: the fixed jaw is constituted by a conductive strip held against the bottom of the trough and provided with transversal serrations in the clamping zone.

11. The electric terminal according to claim 1 further comprising: means for making its mobile parts unlosable.

12. The electric terminal according to claim 11, wherein: the mobile jaw is trapped by the locking screw.

13. The electric terminal according to claim 12, further comprising: a stop which stops the travel of the mobile jaw at the instant when the locking screw is loosened, and the locking screw comprises, at the end of its shank, a cylindrical portion having a diameter smaller than its thread, the length of the threaded portion of the locking screw being such that the latter escapes from the tapping of the ring when the mobile jaw arrives at the end of the travel against the stop and the cylindrical portion remains engaged in the ring. 

1. In an electric axial connection terminal comprising; fixed and mobile jaws; an input face for electric conductor wires on said fixed jaw and an access face for access to the head of an operating screw and for supporting said mobile jaw, said screw moving it linearly along its axis, said clamping jaws and said screw being housed in a body, the improvement wherein: the end of the screw is slightly inclined towards the direction in which the conductor wires are inserted in the fixed jaw, said end being connected to a ring pivoting about an axis perpendicular to that direction, said mobile jaw being provided with means for guiding its movement comprising in cooperation; a pair of lugs with a pair of ramps having a greater inclination in the said direction, so that the sliding of said lugs along said ramps determines the extent of pivoting of said screw.
 2. The electric terminal according to claim 1; wherein: the ring comprises a tapping in which the locking screw moves, and the mobile jaw is fitted onto the locking screw and rests against the shoulder of its head.
 3. The electric terminal according to claim 1, wherein: the ring constitutes a thrust bearing for the end of the shank of the locking screw which keeps it trapped, and the mobile jaw is provided with a bore within which the locking screw rotates.
 4. The electric terminal according to claim 1 wherein: the body of the terminal is constituted by a U-shaped trough at whose bottom the clamping of the conductor wires is effected.
 5. The electric terminal according to claim 2 wherein; the body of the terminal is constituted by a U-shaped trough at whose bottom the clamping of the conductor wires is effected.
 6. The electric terminal according to claim 3 wherein: the body of the terminal is constituted by a U-shaped trough at whose bottom the clamping of the conductor wires is effected.
 7. The electric terminal according to claim 4; wherein: said trough comprises two cut out portions forming ridges facing said ring, each on the rim of the trough at the opposite end to that in which the conductor wires are inserted, and the ring comprises two diameterically opposite studs which rest against said cut out portions, which determine therein, for each inclination of the screw, a pivot axis.
 8. The electric terminal according to claim 4 wherein: the ramps comprise two parallel slots arranged face to face in the wings of the trough and leading to the input face of the terminal, and the mobile jaw comprises two diametrically opposite lugs which slide in the slots, providing a means for guiding it towards the fixed jaw.
 9. The electric terminal according to claim 7 wherein: the ramps comprise two parallel slots arranged face to face in the wings of the trough and leading to the input face of the terminal, and the mobile jaw comprises two diametrically opposite lugs which slide in the slots, providing a means for guiding it towards the fixed jaw.
 10. The electric terminal according to claim 1 wherein: the fixed jaw is constituted by a conductive strip held against the bottom of the trough and provided with transversal serrations in the clamping zone.
 11. The electric terminal according to claim 1 further comprising: means for making its mobile parts unlosable.
 12. The electric terminal according to claim 11, wherein: the mobile jaw is trapped by the locking screw.
 13. The electric terminal according to claim 12, further comprising: a stop which stops the travel of the mobile jaw at the instant when the locking screw is loosened, and the locking screw comprises, at the end of its shank, a cylindrical portion having a diameter smaller than its thread, the length of the threaded portion of the locking screw being such that the latter escapes from the tapping of the ring when the mobile jaw arrives at the end of the travel against the stop and the cylindrical portion remains engaged in the ring. 